In the operation of gas-fueled ovens it is necessary that the burner or burners therein be supplied with suitable quantities of air for proper combustion. Therefore, such ovens are provided in their lower regions with one or more inlet openings through which fresh air may be drawn into the oven. Additionally, the upper regions of the oven are provided with at least one exhaust opening for permitting escape of combustion products generated within the oven during its operation.
It has been found that when the exhaust opening is relatively large, stack action to expel flue products is sometimes difficult to achieve, and any burner flame may become extinguished by the flue products. It has also been found that in some cases when stack action is achieved, the excessive stack action will cause such a flow of air as may prevent the air from being properly supplied to a burner, thus extinguishing the burner or at least causing inefficient burner operation.
A further problem with many prior art gas ovens is that considerable oven heat is lost by uncontrolled stack action which rapidly draws the heat out of the oven with consequent need to operate the burner or burners at higher heat levels.